Armed with new info from downloading a couple of newer versions of the inverter manual, I returned to Cory’s farm to try some new settings. I was confidant I had the answers.
Somewhere between the time of the last blog and this trip I had made some setting changes and the reaction was not as I expected. The newly downloaded manuals showed some extra menu levels not indicated in the original manual. With the strange entry method of the Mate3 terminal, it would be easy to hide some extra menus. As Cory was sampling batteries, I jumped into the menus and found that there were no more! It seems there may have been some software updates missed, so no new menus.
Software updates always worry me. Things can go wrong and then you have nothing. As a rule, my philosophy is if it ain’t broke I won’t try to fix it. Here I was, though, trying to fix it because Tom had not set it up for max performance. The mode selection did not seem to cover our circumstance. We were not off grid. We were not selling power back to the grid. We were not using it as a UPS (uninterruptible power supply). I had chosen Backup Mode, because it seemed to be the least unlikely.
Powered up, the inverter made power. After 5 minutes, it switched the load to grid power. Whaaaat? That’s why I thought there was another menu item. In the revised manuals, there is.
As I was fretting over the lack of the menu item I wanted, I noticed a funny thing: it was working. It had been working since my last visit! Here’s what I think happened. I programmed it correctly, but did not understand some parameters. Many AC devices, like inverters, microinverters or even your home HVAC system have a time delay of 5 minutes before connecting to AC. It’s the law. After running on inverter for 5 minutes, the AC kicked on. In the menu there are two items defaulted to 60 minutes. I think this is where I got tangled up. I was messing with the AC input, so it decided to run on AC for an hour. Then it switched over to normal operation, with the inverter supplying the power.
Since the battery is yet a bit wimpy, the inverter was switching over to grid around sundown and firing back up around 7am, according to the logs. The switch at the house has not been thrown and will not be until we get the batteries in better shape. Still, there is quite a load. The workshop, the hangar and an occupied camper are all powered by the solar and the camper seems to be averaging around 3kw. Its two a/c units run constantly during the day and the resistance heating runs at night. This is NOT an efficient residence for the couple who are staying there. The solar power system is operating about 11 hours a day, at present, so even with one so-so battery Cory is on track to save about $100 on the power bill this month!
The operating battery is improving, at around 50% capacity, now., maybe better. The other one has no bad cells, but is badly sulphated, so I installed a defibrillator (actually, a desulphator) and will let that run a month before lashing them back together and applying a good, long desulphating and equalization charge. After a week on the defib, the hydrometer is at least floating a little on the weaker one. It is a 510 ah battery, so a 1 amp defibrillator takes a while to charge it. Once in EQ mode these batteries will need to hold above 62 volts for quite a few hours and drink a lot of distilled water in the process. Yes, it is a lot of work, but to get 2 giant batteries for the price of a set of golf car batteries will be worth it.
If Cory saves just $100/month, the batteries will soon pay back their cost. Throwing the switch to the house is likely to result in even more saving, even with the current limitations.
Next time we’ll talk about Brad’s OMG 27kw solar power system and how he can make it better. AND how he can stop the power company’s latest move to screw him over.
–Neal